1. Field of the Invention
The present invention relates to a system and method for mounting a traction battery within an automotive vehicle.
2. Disclosure Information
Certain automotive vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and fuel cell vehicles (FCVs), utilize sizable traction batteries, which dwarf conventional 12-volt automotive starting batteries in terms of both size and weight. Traction batteries utilize heavier components and greater volumes of electrolytes which require care to avoid spillage in the event of a collision of a vehicle equipped with such a battery. More precisely, the U.S. National Highway Traffic Safety Administration (NHTSA) Federal Motor Vehicle Safety Standard (FMVSS) 305 mandates performance requirements regarding electrolyte spillage and retention of battery modules mounted in passenger vehicles in the event of a collision up to 48 KPH with a front fixed barrier or 40 KHP if impacted by a rear moving barrier. These requirements are stringent and place demands on vehicle designers seeking to package traction batteries in an efficient manner.
When a traction battery within a EV, HEV or FCV is mounted adjacent the seating area of the vehicle, the integrity of the battery and its mounting system must be maintained. Battery integrity may be preserved in the event of a collision impact having sufficient force and kinetic energy to crush at least part of the floor area to which the battery tray is mounted if the battery tray is moved out of the crush area or crush zone. The present invention accomplishes protection of the battery tray's integrity in a package-efficient manner by dynamically moving the tray out of the crush area at the rear of the vehicle at the time of an impact.
Although it is known to release or move traction batteries in response to an impact, as shown in U.S. Pat. No. 5,555,950 and Japanese Patent 6-48185, such schemes usually result in significant impact upon the battery itself. In contrast, a system and method according to the present invention achieves dynamic relocation of the battery, thereby mitigating the crushing force associated with deformation of the vehicle floor. This distinction is clearly evidenced with respect to the Japanese Patent, which describes a system for mounting battery cells in which the cells are allowed to swing longitudinally in an event of a collision. Unfortunately, this prior art systems will not protect the battery from crushing in the event of longitudinal compression of the vehicle; the system of Japanese Patent 6-48185 merely manages the kinetic energy contained in the batteries. Note that the battery cells of the Japanese Patent swing horizontally and do not at any time leave the plane in which they are originally installed. In contrast, the present inventive system actually rotates the battery to a different positional elevation within the compartment, wherein the battery is much less likely to be damaged by subsequent crushing of the vehicle's floor.